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This is where I post various musings about wildlife and ecology, observations of interesting species (often invertebrates)and bits of research that grab my attention. As well as blogging, I undertake professional ecological & wildlife surveyscovering invertebrates, plants, birds, reptiles, amphibians and some mammals, plus habitat assessment and managementadvice. I don't work on planning applications/for developers. The pages on the right will tell you more about my work,main interests and key projects, and you can follow my academic workhere.

Monday, 23 April 2012

Focusing on the familiar III: earthworms

We all like earthworms. Yes, they are slimy and they wriggle, but they mainrtain our soil and allow us to grow food and garden plants. However, how much attention do we really pay to them? Probably not much, hence this post.

The 'common-or-garden' earthworm Lumbricus terrestris (sometimes called the lobworm) is probably the most familiar (it's the one we study at school) and is what is often being considered when we talk about 'earthworms' in a general way. It is the largest red earthworm in the UK and is often found when digging in gardens or grasslands. Although it's also found in orchards, it is less common in woodlands, farmland and near rivers - other species take over in these habitats - and it isn't even our most common species, even if it the most familiar; that honour may go to the 'grey worm' Aporrectodea caliginosa. Britain has around 45 species compared with 180 in France - the English Channel is a real barrier if you can't fly or swim.

Much is written about L. terrestris so I won't repeat it here - instead I want to look at two rather distinctive species. The first of these is the manure worm (AKA brindling or brandling) Eisenia fetida which is up to around 120mm long.

A pair of Eisenia fetida mating

Close-up of the joined clitellum ('saddle') regions of mating Eisenia fetida. Note how the clitellum is wide and almost encircles the other worm.

Reproduction in earthworms is complex and I'm not going into details here (maybe in another post), but E. fetida is an easy species to find and recognise (note the red and pink banding), hence its inclusion here. It is often found under decaying vegetable matter - manure, compost, wet rotting wood, wet leaf-litter and so on. It's also the only British earthworm to be regularly reported indoors - it pretty thin and can squeeze up between cracks in flooring in old, dilapidated buildings and can even be found in drain-traps and the like i.e. wherever it is damp and there's decaying matter to live in.

The second species, the 'green worm' or 'stubby worm' Allolobophora chlorotica is very different.

Allolobophora chlorotica in garden soil.

A. chlorotica is pale (or if darker, it is greenish rather than red), no more than 80mm long (usually less), and often found in the C-shape illustrated here. It's common in gardens, grasslands, woodlands and in/near wetlands and water-bodies - so, if you see something like this, is isn't necessarily a worm you've cut in half while digging.

This has been a very quick look at just two species, but they are both common and distinctive, so I hope you'll look for them as they go about their essential business, and maybe look out for some other species too. Enjoy!

Further reading

There are plenty of gardening and allotment books that talk about earthworms in general, but I think a good one is:

Morgan, J.A.. (2004). Earthworms, Nature's Gardeners. Osmia, Rothley.

If you want a technical guide to British earthworms, there's really only one title to go for: